This invention relates generally to muffin baking and merchandizing processes and apparatus for baking muffins. More particularly, the invention deals with a continuous process for muffin baking in a humidity controlled spiral oven and a muffin pan for baking, shipping, and merchandising the muffin product.
As used herein, muffins are to be distinguished from other baked products such as cakes, cookies, and breads. Muffins are characterized by a brief baking time, a leavening effected by baking powder, and a cellular texture. By contrast, cakes have a longer baking time, a leavening typically effected by baking soda, and a cohesive texture. Cookies have a short baking time, an absence of leavening, and a cohesive texture. Breads have a long baking time, a yeast leavening, and a cohesive textures.
Some commercial muffin baking processes are batch processes. That is, a quantity of batter is prepared, placed in appropriately shaped pans, and baked-one or more pans at a time. Larger scale commercial baking, however, uses a continuous baking process. In such continuous baking processes, the batter is prepared in such a volume that the baking process can continue virtually without interruption. Individual baking pans are filled at a filling station, advanced through an oven in a continuous succession, allowed to cool in the cooking pans, the pans are inverted to dislodge the baked muffins, and the muffins are packaged and shipped. The empty muffin pans are cleaned and returned to the filling station for reuse.
Such baking processes are replete with problems. For example, the washing of each pan once during each baking cycle consumes large quantities of cleansing water. Waste water treatment imposes an economic burden on these commercial processes. Moreover, periodically each pan must be reglazed with a release coating imposing a further complexity and non-recoverable expense. Furthermore, the inversion and dumping step subject the fragile muffins to a mechanical stress that damages a substantial proportion of them. Periodically pans must be replaced due to that handling damage. Here again, that mechanical damage imposes a further economic burden on the process.
Batch processes for baking muffins have attempted to avoid some of the economic burdens imposed on commercial muffin baking processes by using a plastic muffin tray in which the muffins are baked, shipped, and merchandised. Those muffin trays do not, however, lend themselves to use in continuous processes.
Muffin pans were originally fabricated from metal-a suitable material for use in continuous baking processes. Crystallized polyethylene terephthalate has been proposed for use as an ovenable frozen food tray/cookware combination. (See U.S. Pat. No. 4,737,389, to Harsing, Jr. et at., issued Apr. 12, 1988). Such material, however, is indicated to be quite brittle at temperatures as low as -40.degree. F. making the material only marginally acceptable for use as a frozen food tray material. (See Col. 2, lines 47-51).
Thermoplastics, such as styrene, have been proposed for use as a container for cupcakes. Spiraling or concentric annular grooves can be used in the bottom of the container cells so that the bottom of each recess can move relative to the corresponding sidewall. (See U.S. Pat. No. 3,483,908, issued to Donovan on Dec. 16, 1969). A film or sheet of plastic, paper, or the like can be hermetically sealed to cover the openings of the recesses.
An ornamental design for muffin trays is known which includes a recessed land at the top of each muffin cup. (See U.S. Design Pat. No. D 346,528, issued to Crawford et al. on May 3, 1994).
Other patents of interest include U.S. Design Pat. No. 27,936, issued to Schmidt on Dec. 7, 1987; U.S. Pat. No. 936,232 issued to Musser on Oct. 12, 1909; U.S. Pat. No. 1,719,842 issued to Jackson on Jul. 9, 1929; U.S. Pat. No. 3,099,377 issued to Metzler et al. on Jul. 30, 1963; U.S. Pat. No. 4,296,682 issued to Thompson on Oct. 27, 1981; and U.S. Pat. No. 5,213,227, issued to Koyama et at. on May 25, 1993.